Palladium(II)-, Platin(II)-, Ruthenium(II)-, Rhodium(III)- und Iridium(III)-Komplexe von Desoxyfructosazin

Metal Complexes of Biologically Important Ligands. CIII. [1] Palladium(II), Platinum(II), Ruthenium(II), Rhodium(III), and Iridium(III) Complexes of Desoxyfructosazine The reactions of the pyrazine derivative desoxyfructosazin(pz) with K₂PtCl₄ and with the chlorobridged [M(PR₃)Cl₂]₂ (M = Pd, Pt), [(η⁵-C₅Me₅)MCl₂]₂ and [(η⁶-p-Cymol)RuCl₂]₂ give the watersoluble complexes cis-Cl₂Pt(pz)₂, (R₃P)(Cl)M(pz)M(Cl)(PR₃) (M = Pd, Pt), (η⁵-C₅Me₅)(Cl)₂M(pz)M(Cl)₂(η⁵-C₅Me₅) (M = Rh, Ir), (η⁶-p-Cymol)(Cl₂)Ru(pz)Ru(Cl)₂(η⁶-p-Cymol).     

Magnetic,epr and SOD studies of some Cu(II)-Cu(II), Cu(II)-Ni(II) and Cu(II)-Zn(II) imidazolate bridged complexes

Magnetic, spectroscopic and superoxide dismutase activity of imidazolate bridged [(Salala)Cu-Im-Cu(Salala)]Na, [(Salala)Cu-Im-Zn(Salala)]Na and [(Salala)Cu-Im-Ni(Salala)]Na (Salala=Salicyledenealiniate, Im=Imdiazolate) are described. The epr and electronic spectra of related mononuclear complexes, viz., [(Salala)Cu-OH(2)] and [(Salala)Cu-ImH] also described. Appearance of a half-field signal in polycrystalline and decrease in mu(eff) per copper(II) ion indicate super exchange coupling between copper(II) ion in [(Salala)Cu-Im-Cu(Salala)]Na binuclear complex. A pH-dependent epr and UV-vis study of 50% aqueous DMSO solution of binuclear complexes suggest that the complexes are stable in narrow pH range.     

N,N'-双水杨酰代乙二胺合铜(II)酸根和N,N'-1,2-双水杨酰代丙二胺合铜(II)酸根的Cu(II)-Co(II)双核酸合物的合成和磁性

本文合成了两个新型双核配合物, [Cu(Samen)Co(L)2]和[Cu(Sampn)Co(L)2], Samen^4^-表示N,N'-双水杨酰代乙二胺根阴离子,Sampn^4^-表示N,N'-1,2-双水杨酰代丙二胺根阴离子, L表示5-硝基-1,10-菲咯啉(NO2-Phen)。经元素分析, IR和电子光谱等推定配合物具有酚氧桥结构,Cu(II)及Co(II)的配位环境分别为平面四方及畸变八面体构型。测定了配合物(4-300K)的变温磁化率, 并用最小二乘法和自旋Hamiltonian算符,H=2JS1.S2-DSzl导出的磁方程拟合, 求得交换参数为J=-4.39(Samen)和-3.59cm^-^1(Sampn), 表明两个Cu(II)-Co(II)双核配合物中有弱的反铁磁性超交换相互作用。     

Synthetic, spectral and solution studies on imidazolate-bridged copper(II)-copper(II) and copper(II)-zinc(II) complexes

Synthesis, spectral and solution studies on 2-ethyl imidazolate-bridged (2-EtIm) homo-binuclear copper(II)-copper(II) and hetero-binuclear copper(II)-zinc(II) homologue are described. Magnetic moment values of homo-binuclear complexes indicate that the imidazolate group can mediate antiferromagnetic interactions. Optical spectra of hetero-binuclear complex at varying pH values suggest that the imidazolate-bridged complex is stable over the pH-range 7.15–10.0.     

The equilibrium constants of cadmium(II)-, lead(II)-, magnesium(II)-, and zinc(II)-alpha,beta,gamma,delta-tetrakis(1-methylpyridinium-4-yl)porphine complexes

The equilibrium constants of alpha,beta,gamma,delta-tetrakis(1-methylpyridinium-4-yl)porphine (TMPyP) complexes of cadmium(II), lead(II), magnesium(II), and zinc(II) were spectrophotometrically determined using the absorption spectra at the Soret band and the fluorescence spectra. The values of the following constants at 25 degrees C and ionic strength 0.1M were evaluated: K(PbP) = 10(-8.07 +/- 0.09), K(CdP) = 10(-7.68 +/- 0.03), K(ZnP) = 10(1.72 +/- 0.08), and K(MgP) = 10(-7.40 +/- 0.08) by the acid hydrolysis reaction of the TMPyP-metal complex at various pHs; K(PbP) = 10(-7.80 +/- 0.04) and K(CdP) = 10(-7.38 +/- 0.04) were determined by the ligand exchange reaction between TMPyP and nitrilotriacetic acid.     

Thermal behavior of Cu(II)-, Cd(II)-, and Hg(II)-exchanged montmorillonite complexedwith cysteine

The thermal behavior of montmorillonite and organically modified montmorillonite, both treated with heavy metal cations [Cu(II), Cd(II) and Hg(II)], was characterized via thermal analyses (TG, DTG and DTA) combined with evolved species gas mass spectrometry (MS-EGA), and X-ray diffraction at in situ controlled temperature (HTXRD). The reactions involving Cu(II)- and Cd(II)-montmorillonite samples are mostly related to H₂O and OH loss, unlike Hg(II)-montmorillonite, where effects associated to Hg(II) loss are also present. Finally reactions related to dehydration, dehydroxylation and to organic matter decomposition can be observed in montmorillonite samples treated with cysteine.     

Coordination-position isomeric M(II)Cu(II) and Cu(II)M(II) (M = Co, Ni, Zn) complexes derived from macrocyclic compartmental ligands

The dinucleating macrocyclic ligands (L(2;2))(2-) and (L(2;3))(2-), comprised of two 2-[(N-methylamino)methyl]-6-(iminomethyl)-4-bromophenolate entities combined by the -(CH(2))(2)- chain between the two aminic nitrogen atoms and by the -(CH(2))(2)- or -(CH(2))(3)- chain between the two iminic nitrogen atoms, have afforded the following M(II)Cu(II) complexes: [CoCu(L(2;2))](ClO(4))(2).MeCN (1A), [NiCu(L(2;2))](ClO(4))(2) (2A), [ZnCu(L(2;2))](ClO(4))(2).0.5MeCN.EtOH (3A), [CoCu(L(2;3))(MeCN)(2-PrOH)](ClO(4))(2) (4A), [NiCu(L(2;3))](ClO(4))(2) (5A), and [ZnCu(L(2;3))](ClO(4))(2).1.5DMF (6A). [CoCu(L(2;2))(MeCN)(3)](ClO(4))(2) (1A') crystallizes in the monoclinic space group P2(1)/n, a = 11.691(2) A, b = 18.572(3) A, c = 17.058(3) A, beta= 91.18(2) degrees, V = 3703(1) A(3), and Z = 4. [NiCu(L(2;2))(DMF)(2)](ClO(4))(2) (2A') crystallizes in the triclinic space group P(-)1, a = 11.260(2) A, b = 16.359(6) A, c = 10.853(4) A, alpha= 96.98(3) degrees, beta= 91.18(2) degrees, gamma= 75.20(2) degrees, V = 1917(1) A(3), and Z = 2. 4A crystallizes in the monoclinic space group P2(1)/c, a = 15.064(8) A, b = 11.434(5) A, c = 21.352(5) A, beta= 95.83(2)degrees, V = 3659(2) A(3), and Z = 4. The X-ray crystallographic results demonstrate the M(II) to reside in the N(amine)(2)O(2) site and the Cu(II) in the N(imine)(2)O(2) site. The complexes 1-6 are regarded to be isomeric with [CuCo(L(2;2)))](ClO(4))(2).DMF (1B), [CuNi(L(2;2)))](ClO(4))(2).DMF.MeOH (2B), [CuZn(L(2;2)))](ClO(4))(2).H(2)O (3B)), [CuCo(L(2;3)))](ClO(4))(2).2H(2)O (4B), [CuNi(L(2;3)))](ClO(4))(2) (5B), and [CuZn(L(2;3)))](ClO(4))(2).H(2)O (6B) reported previously, when we ignore exogenous donating and solvating molecules. The isomeric M(II)Cu(II) and Cu(II)M(II) complexes are differentiated by X-ray structural, magnetic, visible spectroscopic, and electrochemical studies. The two isomeric forms are significantly stabilized by the "macrocyclic effect" of the ligands, but 1A is converted into 1B on an electrode, and 2A is converted into 2B at elevated temperature.     

Removal of As(V) by Cu(II)-, Ni(II)-, or Co(II)-doped goethite samples

The present study reports removal of As(V) by adsorption onto laboratory-prepared pure and Cu(II)-, Ni(II)-, and Co(II)-doped goethite samples. The X-ray diffraction patterns showed only goethite as the crystalline phase. Doping of ions in the goethite matrix resulted in shift of d-values. Various parameters chosen for adsorption were nature of adsorbent, percentage of doped cations in goethite matrix, contact time, solution pH, and percentage of adsorbate. It was observed that the pH(pzc) of the goethite surface depended on the nature and concentration of metal ions. The surface area as well as the loading capacity increased with the increase of dopant percentage in goethite matrix. A maximum loading capacity of 19.55 mg/g was observed for 2.7% Cu(II)-doped goethite. The adsorption kinetics for Ni(II), Co(II) and for undoped goethite attained a quasi-equilibrium state after 30 min with almost negligible adsorption beyond this time. In case of Cu(II)-doped goethite samples, the quasi-equilibrium state for As(V) adsorption was observed after 60 min. At each studied pH condition, it was observed that the percentage of adsorption of As(V) decreased in the order Cu(II)-doped goethite > or = Ni(II)-doped goethite > Co(II)-doped goethite > pure goethite. The adsorption followed: Langmuir isotherm, indicating monolayer formation.     

Synthesis, structural characterization, and photophysical, electrochemical, intercomponent energy-transfer, and anion-sensing studies of imidazole 4,5-bis(benzimidazole)-bridged Os(II)Os(II) and Ru(II)Os(II) bipyridine complexes

Homo- and heterobimetallic complexes of composition [(bpy)(2)M(II)(H(2)Imbzim)M'(II)(bpy)(2)](ClO(4))(3)·nH(2)O, where M(II) = M'(II) = Os (1), M(II) = Ru and M'(II) = Os (2), H(3)Imbzim = 4,5-bis(benzimidazole-2-yl)imidazole, and bpy = 2,2'-bipyridine, have been synthesized and characterized using standard analytical and spectroscopic techniques. Both of the complexes crystallized in monoclinic form with the space group P2(1)/m for 1 and P2(1)/n for 2. The absorption spectra, redox behavior, and luminescence properties of the complexes have been thoroughly investigated. The complexes display very intense, ligand-centered absorption bands in the UV region and moderately intense metal-to-ligand charge-transfer (MLCT) bands in the visible region. The bimetallic complexes show two successive one-electron reversible metal-centered oxidations. The strong fluorescence of free H(3)Imbzim is completely quenched in the metal complexes by energy transfer to the metal-based units, which exhibit their characteristic MLCT phosphorescence. The luminescence data of the heterometallic complex 2 show that electronic energy transfer takes place from the ruthenium center to the osmium-based component. The anion binding properties of the complexes have been studied in solutions using absorption, emission, and (1)H NMR spectral measurements. The metalloreceptors act as sensors for F(-) and AcO(-) ions. Sensing studies indicate the presence of two successive anion-induced deprotonation steps, leading to the formation of [(bpy)(2)M(HImbzim)M'(bpy)(2)](2+) and [(bpy)(2)M(Imbzim)M'(bpy)(2)](+) species. Double deprotonation is also observed in the presence of hydroxide. The binding affinities of different anions toward the receptors have been evaluated. Cyclic voltammetry measurements carried out in acetonitrile have provided evidence in favor of anion-dependent electrochemical responses of the bimetallic metalloreceptors with F(-) and AcO(-) ions.     

Diaza-crown-N,N-dialkanoic acids copper(II) and dicopper(II) complexes

Twelve-, fifteen-, and eighteen-membered diaza-crown-N, N-′dialkanoic acids LH₂ and their inner salt copper(II) complexes CuL and dicopper complex [CuL(3). CuCl₂. CH₃OH_n were obtained. The complexes of 15- and 18-membered ligands contain Cu²⁺ ion inside the ring.     

Equilibrium studies of Mn(II), Mg(II), Ca(II), Sr(II) and Ba(II) withp-fluoro-,p-chloro-,p-bromo-,p-methyl-benzoylacetones and 1-(4-fluorophenyl)-1,3-pentanedione

The rawpH-data, obtained from the potentiometric titrations of the titled ligands with NaOH in 75% (v/v) dioxane-water mixture performed at 20, 30 and 40°C at constant ionic strength (=0.1M-NaClO₄), have been adequately corrected for dilution, and solvent effects in order to evaluate thermodynamic dissociation constants. Variance of the latter as a function of temperature has also been accounted for. The differing magnitudes of thermodynamic dissociation constants of the titled ligands have been explained on the basis of the non coplanar orientation of the phenyl ring in the ligands and a comparison has been made with those of unsubstituted benzoylacetone, dibenzoylmethane and acetylacetone.Following similar technique, thermodynamic stepwise and overall formation constants of the titled metal-ligand systems have been obtained and the results correlated with ligand basicity inverse metal crystal radii and second potentials of metals. Decrease in the free enthalpy (–G) of complexation reaction has also been evaluated.

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Untersuchung der Gleichgewichte von Mn(II), Mg(II), Ca(II), Sr(II) und Ba(II) mit p-Fluor-, p.-Chlor-, p-Brom-, p-Methyl-benzoylaceton und 1-(4-Fluorphenyl)-1,3-pentanedion

Zusammenfassung Aus der potenitometrischen Titration der Titelverbindungen mit NaOH in 75 (v/v) Dioxan—Wasser bei, 20, 30 und 40°C bei konstanter Ionenstärke (=0,1M-NaClO₄) wurden die thermodynamischen Dissoziationskonstanten ermittelt. Verdünnungs-, Lösungsmittel-und Temperatureffekte wurden berücksichtigt. Die unterschiedlichen Dissoziationskonstanten werden mit der Nichtplanarität des Phenylrings in den Liganden erklärt. Außerdem wurden die Komplexbildungskonstanten bestimmt; sie sind in die Diskussion miteinbezogen.

     

Bis(dimethylmetall(III)glyoximato)metallate(II) (metall(III) = Al,Ga, In,metall(II) = Ni,Pd, Pt,Cu)

When the trimethyl derivatives of aluminium, gallium and indium react with glyoximato metallates, (R₂C₂N₂(O)OH)₂Met^II (R = H, CH₃; Met^II = Ni, Pd, Pt, Cu), in a $\text{2}\text{1}$ molar ratio, 2 mol of methane are evolved and monomeric bis(dimethylmetal(III)glyoximato)metallates(II) (metal(III) = Al, Ga, In) are formed in high yields. The vibrational and NMR spectra of the new complexes were measured and were partly resolved. The X-ray structure determinations of two of these compounds show non-planar structures of approximate C_2h and C₂ symmetry, respectively, with weak metal(III)?metal(II) π-interactions.     

N,N'-乙二水杨酰胺合铜(II)酸根和N,N'-1,2-丙二水杨酰胺全铜(II)酸根的双核Cu(II)-Fe(III)配合物的合成和磁性

本文合成了四个新型双核配合物、[Cu(samen)Fe(L)Cl]和[Cu(sampn)Fe(L)Cl]。经元素分析、IR, 电导、磁性测量等手段推定配合物具有酚氧桥结构, Cu(II)及Fe(III)的配位环境分别为平面四方及四角锥的构型, Fe(III)离子的自旋态S=3/2。测定了配合物[Cu(samen)Fe(L)Cl]的变温磁化率(4-300K), 参数J和θ值表明两个双核配合物中金属离子之间有中等程度的反铁磁性超交换作用和双核单元之间有弱的分子间相互作用。     

Synthesis, structure, magnetism, and spectroscopic properties of heterobinuclear copper(II)-zinc(II) complexes and their copper(II)-copper(II) analogues in asymmetric ligand environments

Heterobinuclear copper(II)-zinc(II) complexes and their homobinuclear dicopper(II) counterparts (1-4) of two asymmetric ligands (H2L1 and H2L2), based on 2-aminocyclopent-1-ene-1-dithiocarboxylate, are reported. The ligands are capable of providing both donor set and coordination number asymmetry in tandem. Metal centers in these complexes are connected by a micro-alkoxo and a bridging pyrazolate moiety, as confirmed by X-ray structure analyses of 1, 3, and 4. The Cu(1) site in the dicopper complex (1) is square planar and so are the copper sites in the Cu-Zn complexes 3 and 4. The pentacoordinated Zn sites in the latter complexes have distorted TBP geometry (tau = 0.74), while the corresponding Cu site in 1 has a highly distorted square pyramidal structure (tau = 0.54). The Cu...Zn separations in 3 and 4 are 3.3782 and 3.3403 angstroms, respectively, while the Cu...Cu distance in 1 is 3.3687 angstroms. The dicopper complexes are EPR silent at 77 K, in which the copper(II) centers are coupled by strong antiferromagnetic coupling (J = ca. -290 cm(-1)) as confirmed by variable-temperature (4-300 K) magnetic measurements. These compounds (1 and 2) undergo two one-electron reductions and a single step two-electron oxidation at ca. -0.26, -1.40, and 1.0 V vs Ag/AgCl reference, respectively, as indicated by cyclic and differential pulse voltammetry done at subambient temperatures. EPR spectra of 3 and 4 display axial anisotropy at 77 K with the gperpendicular region being split into multiple lines due to N-superhyperfine coupling (AN = 15.3 x 10(-4) cm(-1)). The observed trend in the spin-Hamiltonian parameters, gparallel > gperpendicular > 2.04 and |Aperpendicular| < |Aparallel| approximately (120-150) x 10(-4) cm(-1), indicates a d(x2-y2)-based ground state with tetragonal site symmetry for the Cu(II) center in these molecules.     

Peculiarities of Chemical Binding in Anhydrous Lead(II) and Tin(II) Hexacyanoferrates(II,III)

The electronic structure and chemical binding of anhydrous lead and tin hexacyanoferrates(II,III) Pb₂Fe(CN)₆, Pb_1.5Fe(CN)₆, and Sn₂Fe(CN)₆ were studied by the linear muffm-tin orbital (tight binding approximation) and extended Hückel theory methods. The general tendencies of variation for the stability of the Pb–N, Sn–N, Fe–C, and C–N bonds were determined for Pb₂Fe(CN)₆, Pb_1.5Fe(CN)₆, and Sn₂Fe(CN)₆ crystals. Peculiarities of Pb(Sn)–N chemical interactions in the structure of the phases have been found.     

Den mikrochemischen Nachweis von Quecksilber (II)-, Kupfer(II)- und Kobalt(II)-Salz

Ohne Zusammenfassung